The ATP Finals enter a new era on Sunday when the season-ending tournament gets under way at the Pala Alpitour in Turin, Italy following a 12-year stay in London.
There may have been a change in location, and the event will feature a few new names, but the format remains the same: the top eight male players, based on ranking points accumulated throughout the season, battle it out in two round robin groups, with the top two from each advancing to the knockout semi-finals. There will be both singles and doubles tournaments.
Points and prize money are distributed based on victories. If the eventual champion successfully navigates his way to the title without losing a match, he will claim the maximum 1500 points and $2.316 million. However, if the champion claims the title having a lost a match en route, he will be awarded 500 points and prize money of $1.094 million.
Following the Paris Masters last week, the top eight singles players are now locked and have made their way to Italy for the final tournament of the 2021 season. Here is a look at who's competing and how they punched their ticket for Turin.
For stats on all eight players, browse through the photo gallery above.
Novak Djokovic (ATP ranking: 1)
It has been another season of Djokovic domination on the ATP Tour. The 34-year-old Serb was within touching distance of the calendar Grand Slam but fell just short in the US Open final. Still, a year comprising a record-extending ninth Australian Open title, his second Roland Garros triumph, and a sixth Wimbledon crown represents an astonishing achievement.
Djokovic, who will end the year world No 1 for a record seventh time, wrapped up his regular season in Paris with his 37th Masters title - his 86th overall - and arrives in Turin seeking his sixth ATP Finals trophy on his 14th appearance. However, it has been six years since he won the season-finale event having won four in a row from 2012 to 2015. Regardless, he remains the man to beat - as he does at every tournament.
Daniil Medvedev (ATP ranking: 2)
The defending champion returns to the tournament following another superb campaign, highlighted by his Grand Slam breakthrough. It was third time lucky for Medevedev, who thrashed Djokovic in the US Open final for his first major title having lost his previous two Grand Slam finals, including to Djokovic at the Australian Open in February.
His triumph in New York was one of four titles in 2021 including his fourth Masters, at the Canadian Open, and the 25-year-old Russian returns to the ATP Finals aiming to continue his unbeaten streak at the tournament, which earned him maximum points and prize money 12 moths ago.
This will be his third successive appearance at the ATP Finals having made his debut in 2019.
Alexander Zverev (ATP raking: 3)
The 2018 ATP Finals champion is arguably in the form of his life following his gold medal victory at the Tokyo Olympic Games. Zverev, 24, followed that up with his fifth Masters title, in Cincinnati, and claimed the Vienna trophy. He has won five tournaments in 2021 and reached the semi-finals of the French Open and US Open.
Turin will be the German's fifth successive appearance at the ATP Finals, although he will want to improve on last year's showing when he was unable to progress from the group. Now at his career-high ranking, Zverev has the form to go all the way.
Stefanos Tsitsipas (ATP ranking: 4)
Tsitsipas enjoyed a dream debut at the ATP Finals in 2019 when he became the tournament's youngest winner in 18 years. He returns for his third straight appearance following another fine season, particularly in the first half of the year.
The 23-year-old Greek reached the semi-finals of the Australian Open and his first Grand Slam final at Roland Garros, where he led Djokovic by two sets to love, only for the Serb to fight back and claim the title. There have been two titles in 2021 for Tsitsipas, including his first at a Masters event, achieved in Monte Carlo.
There is a minor question mark about Tsitsipas' fitness after he retired from his most recent match, at the Paris Masters, with an arm injury, although he insisted it was a precautionary measure ahead of Turin.
Andrey Rublev (ATP ranking: 5)
The 24-year-old Russian is set to make his second successive ATP Finals appearance following another season of great consistency. Although Rublev only won one title in 2021, at the Rotterdam Open, he reached two Masters 1000 finals, in Monte Carlo and Cincinnati. He now sits at his career-high ranking.
Rublev's ATP Finals debut ended with a round robin exit, but his improvements over the past year will give him the confidence of a better showing this time around.
Matteo Berrettini (ATP ranking: 7)
The Italian takes the sixth place at the ATP Finals in the injury-absence of Rafael Nadal, qualifying after a career-best season. Berrettini, 25, claimed two titles in 2021 and reached his first Grand Slam final at Wimbledon. He also reached his first Masters 1000 final, in Madrid.
Berrettini, who sits at his career-high ranking, is making his second ATP Finals appearance following his debut in 2019. He was a non-playing alternate last year. He has the power and game to go far in Turin.
Casper Ruud (ATP ranking: 8)
It has been some season for the 22-year-old Norwegian, who has a 100 per cent conversion rate in finals in 2021, winning five titles. At one stage, he won three tournaments in a row, and only three players - Zverev, Tsitsipas, and Medvedev - have won more matches on tour this year.
Ruud will be making his debut appearance at the ATP Finals and as a clay court specialist, it will be interesting to see how he fares against the world's best on indoor hard courts.
Hubert Hurkacz (ATP ranking: 9)
There is often a player who seals his spot at the last moment, and this year's honour goes to Hurkacz, who booked his place in Turin by reaching the Paris Masters semi-finals.
The Pole's presence at the ATP Finals is just reward for a superb breakthrough season, which has comprised three titles including at the Miami Masters. His current ranking of No 9 is a career high.
Hurkacz, 24, will be making his debut at the ATP Finals and could be a dark horse if not for the title, then to reach the semi-finals.